Folding systems for folding disposable worn articles have been proposed in the art (see the first to third patent documents below). For example, in the second patent document, end portions of an article are folded by swing arms adjacent to a member for holding the article. However, the swing arms only swing so as to lift up end portions of articles, and if pliant portions such as flaps of worn articles are attempted to fold with such a folding device, variations may occur in the fastening positions.